A Catholic bishop remains in custody, days after being arrested in northeastern China. A U.S. monitoring group says the detention fits a pattern of China's persecution of underground Roman Catholic Church members and clergy.

The Cardinal Kung Foundation in the United States says Bishop Wei Jingyi was arrested on Friday in northeastern China. The president of the foundation, Joseph Kung, says Bishop Wei had just picked up two "foreign friends" at the airport in Harbin, and was arrested at a toll booth on his way back.

"All I know is that he was picked up while he tried to pay his toll," says Mr. Kung. "We don't know where he was being held, we don't know why he was being held."

China's communist government is officially atheist and broke ties with the Roman Catholic Church in the 1950s. It does, however, permit worship in official government-sanctioned churches, which disavow Vatican leadership and reject the Pope's right to appoint bishops.

An estimated five million Chinese belong to Beijing's official Catholic Church - half the estimated 10 million believed to adhere to what is called the "underground" Catholic Church.

Mr. Kung, says Bishop Wei has served several terms in Chinese labor camps for his activities in the underground church. He says one of Bishop Wei's key activities has been to lead informal, secret worship sessions outdoors or in private homes. "Once they are found, many times security bureau just came in and arrest everybody and take the priest away and so forth and, you can hardly imagine that," he says.

Mr. Kung says about 26 Roman Catholic clergy members are in Chinese prisons at this time.

News of Bishop Wei's arrest comes just days after Beijing released Wang Youcai, a key organizer of the 1989 Tiananmen Square protests. Beijing has also recently released a Christian from Fujian, who was imprisoned two years ago for trying to smuggle Bibles into China.